Los Bracitos tree frog  (Hypsiboas heilprini)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The Los Bracitos tree frog is an inconspicuous species with a cryptic colouration that blends into the foliage of Hispaniola’s rainforest. With a uniform green back, head and legs, the Los Bracitos tree frog is extremely well camouflaged. Whilst perched, starkly contrasting yellow-orange hands and feet, and bright orange toe webs are concealed under the body, while the undersides are pale-yellow to orange, with a cream throat and vent (2). The Los Bracitos tree frog displays the characteristic tree frog shape with a large, wide, mouth and conspicuous eyes on a broad head, while the limbs are extremely flexible. As its common name alludes, the Los Bracitos tree frog is an accomplished climber, and enlarged adhesive disc-shaped pads at the tips of the digits allow it to cling to vegetation and climb with great agility (3) (4). The small, dark coloured tadpole has a thick, short, muscular tail, and an elongated caudal fin (2).

The Los Bracitos tree frog is endemic to the Caribbean Island of Hispaniola (consisting of Haiti and the Dominican Republic). It is found throughout the island in highly fragmented populations (1).

The Los Bracitos tree frog inhabits montane fast-flowing streams in tropical broadleaved forests. It is found from sea-level up to 1,850 metres, but is most abundant at higher altitudes (1) (2).

In common with other frogs and toads, the Los Bracitos tree frog is a carnivore, feeding largely on insects (3). A sit-and-wait predator, it detects its prey with acute eyesight, capturing its target on the sticky upper surface of its long paddle-like tongue. In contrast, the free-swimming tadpoles have a vegetarian diet, using fleshy lips and horny teeth to rasp at algae and aquatic plants (4). 

Males attract females using raucous, mechanical-like calls, advertising themselves from conspicuous positions on prominent rocks or vegetation (2). Mating takes place in shallow water, and the male clasps the female behind the front limbs, initiating fertilisation, and the resulting fertilised eggs are laid in the wall of a moist streamside cave (2) (3). It is possible that the Los Bracitos tree frog breeds in the same pond each year, using environmental cues, such as smell and humidity, to locate the breeding grounds. As is typical of the humid tropics, breeding is not dependant upon seasonal fluctuations in rainfall and temperature, and pairs may mate at any time of the year (4).

The skin of the Los Bracitos tree frog is very thin and permeable, with a rich supply of blood vessels that allow the frog to absorb water through its skin whilst submerged. As a result, it has little control over water loss from its body, and so during periods of drought or high temperature, the Los Bracitos tree frog will alter its body posture to expose more or less of its body surface to the prevailing conditions (4).         

Restricted to just a single island that is heavily populated, the greatest threat to the Los Bracitos tree frog is the degradation of montane forest streams (1). The island of Hispaniola is one of the most heavily degraded landscapes in the world, with only 10 percent of original forest cover remaining in the Dominican Republic, and a saddening, one percent remaining in Haiti (5). Much of the forest has been converted to coffee and tobacco plantations, while the expansion of agricultural land, using slash-and-burn techniques, has destroyed vast areas of forest (6). Consequently, deforestation has caused the Los Bracitos tree frog to disappear from much of its former range, leaving highly fragmented, relict populations (1). Furthermore, mining in the Dominican Republic, pollution and soil erosion have been identified as further threats to the survival of the Los Bracitos tree frog (1).  

Although there are no known conservation measures in place for the Los Bracitos tree frog, it is found in several protected areas, including Reserva Científica Natural de Valle Nuevo (1). There are 22 reserves in the Dominican Republic, but the creation of an additional 15 reserves has been proposed, a measure that would significantly increase the level of protection afforded this species’ dwindling habitat (6).    

View information on this species at the UNEP World Conservation Monitoring Centre.

For more information on the conservation of amphibians, see:

• The IUCN/SSC Amphibian Specialist Group: 
  http://www.amphibians.org/